Newb Exchange Question

J

JAW

Gawd
Joined
Feb 8, 2004
Messages
518
I have found out that our company's e-mail server has been listed in a spam list. After looking at our exchange 2000 server, I realized whoever had set it up was allowing open relays, after disabling that I want to remove us from the spam list. To do this, you have to be able to recieve a reverse dns e-mail from the spam list site. How do I setup exchange to catch msgs from that domain? Right now it's setup for ourdomain.com, but how do I add the reverse dns domain such as bleh.xxx.xxx.xxx.xxx.gte.net, to recieve the e-mail? Basically a standard [email protected], I am currently getting cannot relay errors back.
 
what exactly would I need to add to the dns? Right now, our isp points the dns record from domain.com to mail.domain.com for the mx record. Which is our inhouse exchange server. Our isp controls our dns records, so should I have them add an A line for bdsl.xx.xx.xxx.xx.gte.net then an mx record pointing that to mail.domain.com?
 
i think what you need is to call them and tell them you need a PTR record for the same box they have an MX record for. they already have the MX record so they shouldn't actually require any actual info from you.
 
actually, i've been getting emails all day from a listserve where the subject of reverse DNS lookups for blocking spam came up. the latest email may provide some info relevant to your situation.
Regarding DNS and PTR records, one should go to the definitive definitions, that is the Internet Society's (ISOC's) RFCs. RFC 1912, i.e. "Common DNS Operational and Configuration Errors" (see
http://www.faqs.org/rfcs/rfc1912.html ) states that:
Make sure your PTR and A records match. For every IP address, there
should be a matching PTR record in the in-addr.arpa domain. If a
host is multi-homed, (more than one IP address) make sure that all IP
addresses have a corresponding PTR record (not just the first one).
Failure to have matching PTR and A records can cause loss of Internet
services similar to not being registered in the DNS at all. Also,
PTR records must point back to a valid A record, not a alias defined
by a CNAME. It is highly recommended that you use some software
which automates this checking, or generate your DNS data from a
database which automatically creates consistent data.
Click to expand...
Whereas this RFC does not "mandate" the use of PTR records (reverse DNS records), it does indicate that PTR records "should" exist.

The convention for too many mail systems, including AOL and many, many others is to check for the DNS PTR record and reject all mail that does not have a PTR record for an incoming mail sent from a given mail host.

We recommend (strongly) that all simple mail transfer protocol (SMTP) hosts have a PTR record to match the address (A) record for that host.

I hope this helps.
Click to expand...
 
for the reverse dns to work, you may have to connect through a smarthost.
in the connectors folder, go to the properties page of smtp. i have mine set to fwd all mail through this connector to the following smarthosts.
then in that field i have the smarthost of my isp there. this gets us a good reverse dns lookup.
 
how does the smarthost result in the reverse DNS record? perhaps your ISP has done a proper mail configuration with regards to DNS records and since you go through them you benefit from that. simply enabling a smarthost will not provide correctly configured DNS though . . . if you have information to the contrary though please share it.

thanks
 
DNS is in, but I still get this error.

This is an automatically generated Delivery Status Notification

Delivery to the following recipient failed permanently:

[email protected]

Technical details of failure:
PERM_FAILURE: SMTP Error (state 10): 550 5.7.1 Unable to relay for [email protected]

Do I need to fix dns or my exchange server?
 
most isp's hold the authourity for PTR records on public ip address given to their customers. most likely you'll have to contact your isp so that your authoritive for the reverse zone (if they give you your own small subnet) or have them change it themselves.
 
Can't we just change it in our DNS? Also I don't understand why dns is required for our exchange server to deliver an e-mail with the servers ip as reverse dns. It'll accept [email protected], but won't accept the reverse dns?
 
Because of what i said above. your dns server is not authoritive for that zone. only for the forard lookup zone. contact your isp and/or registrar.
 
Hi, joining this thread because of mail message posted by JAW before
my problem is quite bigger (I think ;P) because I even can send mail from exchange to outside world but no chance to receive (exchange will auto reply that mail) and eihter sending mails between mailboxes on the server doesn't work(Yes I am installing a band new exchange server)
have somebody any ideas to help me?
THX
 
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